A Shipborne Antenna for Maritime Satellite Communications

From a cost effectiveness point of view, the shipborne antenna is usually considered the most critical component in a shipborne terminal for maritime satellite communications (MARSAT). For possible use in such a system, a high gain autotrack antenna has been developed. The antenna utilizes a combined electronical and mechanical beam steering realized with two planar phased arrays mounted on a mechanical axis. The antenna system is designed for unmanned operation, utilizing an automatic search-and-track mode. After acquisition of a beacon signal from the satellite, a monopulse track mode keeps the antenna pointing position locked, to the direction of incident beacon signal, irrespective of the motions of the ship. Attention has been paid to multipath effects that may occur, in particular reflections from the surface of the sea. This paper is concerned with the design background and the development of the antenna system.     

Risk informed decision-making and its ethical basis

In decision-making under uncertainty there are two main questions that need to be evaluated: (i) What are the future consequences and associated uncertainties of an action, and (ii) what is a good (or right) decision or action. Philosophically these issues are categorized as epistemic questions (i.e. questions of knowledge) and ethical questions (i.e. questions of moral and norms). This paper discusses the second issue, and evaluates different risk management approaches for establishing good decisions, using different ethical theories as a basis. These theories include the utilitarian ethics of Bentley and Mills, and deontological ethics of Kant, Rawls and Habermas. The risk management approaches include cost–benefit analysis (CBA), minimum safety criterion, the ALARP principle and the precautionary principle.